François Hollande, the French Socialist candidate in presidential election held out an olive branch to Britain yesterday, saying it should feel "part of Europe".

But the man most likely to be France's next President warned David Cameron that any attempt to create a "sanctuary" from regulation for the City of London was "not acceptable".

Mr Hollande will visit London on 29 February to speak to the Labour leader, Ed Milliband, and perhaps the Prime Minister.

In a meeting with British and American journalists, he said: "We need a Great Britain that will take its place in Europe."

The polls place Mr Hollande way ahead of Nicolas Sarkozy, the incumbent conservative, who is expected to officially launch his re-election bid this week.

Mr Hollande sent ripples of alarm in the City last month by laying into "big finance", calling the international finance system his "greatest adversary" in his first major campaign rally.

Yesterday, he warned that Britain could not expect to escape more financial regulation, despite Mr Cameron's decision not to sign the recent European fiscal pact.

"David Cameron's attempt to create a sanctuary from regulation for the City of London is not acceptable," he said.

This issue sparked an angry spat between Mr Cameron and President Sarkozy, along with other EU governments at the Brussels summit in December.

But Mr Hollande's overriding message was that Britain and the City of London need not overly fear a Socialist French presidency. His ideas for financial market regulation were not "overboard," he insisted. These and his ideas on fostering growth were similar to those outlined by President Barack Obama in his state of the union address in January.

If elected President on 6 May, Mr Hollande pledged to try to improve cross-Channel ties strained in recent weeks over differences in handling the euro debt crisis and more recently Mr Cameron's dismissal of French attempts to create a "Robin Hood" tax on financial transactions.

He said he was "free" to meet Mr Cameron, adding: "I can understand that a head of government might not want to meet a presidential candidate when he has a relationship with the President (of France)."

The Prime Minister, yet to reply, will meet President Sarkozy in Paris on Friday for an Anglo-French defence summit - the first direct contact he has had with the French leader since their Brussels row.

Mr Hollande had warm words for Tony Blair, who is unpopular with the French Left, describing the former New Labour leader as "so intelligent he doesn't need to be arrogant".

Mr Blair had "shown the way" to the Left in Europe simply by winning three consecutive elections, Mr Hollande said, but also by"rebuilding the health and education systems in Britain after long years of conservatism". The French Left learned from his pragmatism, he said. "It wasn't about Right or Left, it was about if it worked or didn't work".

But Tony Blair's "great mistake", he went on, was to "swallow the dangerous idea that markets could always regulate themselves".

Mr Hollande, 57, said he was prepared for an "aggressive" campaign once Mr Sarkozy – whom he refused to name - joins the race proper.

He re-iterated his promise to "amend" the EU fiscal discipline pact to introduce a new chapter on growth-creation, saying his first trip abroad if elected would be to visit Chancellor Angela Merkel of Germany, who has thrown her weight behind Mr Sarkozy.

Mr Hollande would not be drawn about his romantic partner, Valérie Trierweiler, a TV and Paris Match journalist, who was also present at the meeting. "Oh she's just here as part of the Anglo-Saxon press," Mr Hollande said.

When asked why any right minded person would wish to be presidency in such harsh economic times, he said: "I ran because I felt that, at this time, and perhaps no other, I happen to offer the blend of qualities which will allow (France) to succeed: stability, serenity, reflection, restraint."